JP2011173423A - Copper-clad laminated substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a copper-clad laminated substrate which is improved in slip performance and skid property in the surface, favorable in appearance, and high in flexibility. <P>SOLUTION: The copper-clad laminated substrate is prepared by laminating copper foil at one side or both sides of a polyimide film by thermocompression bonding. The polyimide film has a heat-resistant polyimide layer and a thermoplastic polyimide layer. The copper-clad laminated substrate is formed by laminating the copper foil at one side or both sides of the heat-resistant polyimide layer via the thermoplastic polyimide layer by thermocompression bonding. Polyimide particles are dispersed in the thermoplastic polyimide layer. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a highly flexible copper-clad laminated substrate obtained by laminating a copper foil on a polyimide film.

  Polyimide films have been used for laminates, flexible printed boards, and the like because of their excellent heat resistance, chemical resistance, mechanical strength, electrical properties, and the like.

  For example, as a flexible printed wiring board (FPC), a copper-clad laminated board formed by laminating a copper foil on one side or both sides of a polyimide film is used (Patent Documents 1 to 3). The polyimide film used is usually about 25 μm thick as in Examples of Patent Documents 1 to 3.

  Currently, excellent mechanical properties and high flexibility are demanded for copper-clad laminates, including substrates for electronic components. In particular, high flexibility is required when a copper-clad laminate is applied to the hinge portion. However, the conventional copper-clad laminate using a polyimide film having a thickness of about 25 μm does not have sufficient flexibility.

  Moreover, a polyimide film has a problem in adhesiveness. As a method for improving the adhesiveness, a surface treatment such as alkali treatment, corona treatment, sand blasting, and low-temperature plasma treatment is performed. However, although these methods are effective in improving the adhesiveness, an adhesive other than polyimide, for example, an epoxy resin adhesive is required as an adhesive, and the heat resistance of the entire flexible substrate is lowered.

  For this reason, the thermocompression-bonding multilayer polyimide film which laminated | stacked the thin layer of the thermoplastic polyimide on both surfaces of the heat resistant polyimide layer was proposed as a polyimide film.

  However, when the surface of this thermocompression-bonding multilayer polyimide film is smooth, the friction between the roll and the like is large when producing a film to be wound on a winding roll or when laminating with copper foil, and wrinkles may occur. The trouble of winding around a roll may occur, and winding is limited. Therefore, it was necessary to improve the surface slipperiness of the polyimide film.

  As a method for improving the surface smoothness of the polyimide film, for example, a surface treatment such as embossing, or inorganic powder such as calcium phosphate (Patent Document 1) or silica (Patent Document 2) is dispersed in the polyimide film. And a method of reducing the friction coefficient of the surface by causing fine protrusions on the film surface. In addition, a method for producing a polyimide film by casting a polyamic acid solution polymerized in a solvent in which fine inorganic fillers are dispersed has been proposed (Patent Document 3).

  However, the first method of surface treatment has a drawback that excessive irregularities are generated on the film surface and the appearance of the film is easily impaired. In the second method, an inorganic powder is mixed with a polyamic acid solution to produce a polyimide film. However, it is difficult to uniformly disperse the inorganic powder in the polyamic acid solution unless a special dispersing device is used. Therefore, in this method, the inorganic powder may remain as a lump without being dispersed, and large protrusions may be formed on the resulting film surface. Similarly, in the third method, it is difficult to uniformly disperse the fine particle inorganic powder, and the use of an inorganic powder having a large particle size may cause the same problem as in the second method.

  For this reason, in the copper-clad laminated substrate for COF where a fine pattern is required, when the method of adding these inorganic fillers is applied, the protrusions on the surface of the thermoplastic polyimide may obstruct the formation of a fine pitch.

JP-A-62-68852 JP 62-68853 A JP-A-6-145378

  An object of the present invention is to provide a copper-clad laminate having high flexibility. Furthermore, another object of the present invention is to provide a copper-clad laminate having improved flexibility and smoothness on the surface of a polyimide film, a good appearance and high flexibility.

  The present invention relates to the following matters.

1. It is a copper-clad laminated board formed by laminating copper foil on one or both sides of a polyimide film by thermocompression bonding,
The thickness of the polyimide film is 5 to 20 μm,
A copper-clad laminate having a copper foil thickness of 1 to 18 μm.

2. The polyimide film has a heat-resistant polyimide layer and a thermoplastic polyimide layer,
2. The copper-clad laminate substrate according to 1 above, wherein the copper-clad laminate substrate is a copper-clad laminate substrate obtained by laminating a copper foil by thermocompression bonding on one or both sides of a heat-resistant polyimide layer via a thermoplastic polyimide layer.

  3. 2. The copper-clad laminate as described in 1 above, wherein the polyimide film has a thickness of 5 to 15 μm.

  4). 2. The copper-clad laminate as described in 1 above, wherein the copper foil is a rolled copper foil having a thickness of 8 to 18 μm.

  5. 5. The copper-clad laminate as described in 4 above, wherein the copper foil is a rolled copper foil having a thickness of 10 to 18 μm.

  6). 6. The copper-clad laminate as described in 5 above, wherein the copper foil is a rolled copper foil having a thickness of 10 to 12 μm.

7). The copper foil is a rolled copper foil having a tensile strength before heat treatment of 300 N / mm ² or more and a tensile strength ratio after heat treatment at 180 ° C. for 1 hour of 33% or less defined by the following formula (1): 33% or less The copper-clad laminate as described.
Tensile strength ratio after heat treatment (%) = tensile strength after heat treatment / tensile strength before heat treatment × 100 (1)

8). The copper foil is a copper foil with a carrier,
2. The copper-clad laminate as described in 1 above, wherein the thickness of the copper foil from which the carrier is peeled is 1 to 5 μm.

  9. A copper-clad laminate obtained by peeling the carrier from the copper-clad laminate described in 8 above and then adjusting the thickness of the copper foil to 5 to 8 μm by copper plating.

  10. 2. The copper-clad laminate as described in 1 above, wherein the MIT folding resistance is about 2000 times or more.

  11. The copper-clad laminate as described in 9 above, wherein the MIT folding resistance is about 2000 times or more.

  12 2. The copper-clad laminate according to 1 above, wherein the polyimide film is a thermocompression-bonding multilayer polyimide film having a thermoplastic polyimide layer on one side or both sides of the heat-resistant polyimide layer.

  13. 13. The copper-clad laminate as described in 12 above, wherein polyimide particles are dispersed in the thermoplastic polyimide layer.

14 The polyimide film having a median diameter of 0.3 to 0.8 μm and a maximum diameter of 2 μm or less in a thermoplastic polyimide layer of at least 0.5 μm from the surface thereof is about 0. It is dispersed at a rate of 5 to 10% by mass, does not substantially contain inorganic powder,
14. The copper-clad laminate as described in 13 above, wherein the polyimide film has a friction coefficient of 0.05 to 0.7.

  15. 14. The copper-clad laminate as described in 13 above, wherein the polyimide particles are obtained from a pyromellitic acid component and a p-phenylenediamine component.

  16. 13. The copper-clad laminate as described in 12 above, wherein the polyimide film has a thermoplastic polyimide layer having a thickness of 1 to 6 μm on both sides of a heat-resistant polyimide layer having a thickness of 3 to 18 μm.

  17. 13. The copper-clad laminate as described in 12 above, wherein a thermocompression-bonding multilayer polyimide film and a copper foil are thermocompression bonded under pressure at a temperature not lower than the glass transition temperature of the thermoplastic polyimide and not higher than 400 ° C.

  18. 13. The copper-clad sheet as described in 12 above, wherein the thermocompression-bonding multilayer polyimide film is obtained by laminating and integrating a thermocompression-bonding polyimide layer on one side or both sides of a heat-resistant polyimide layer by a coextrusion-casting film forming method. Laminated substrate.

  19. The copper-clad laminate as described in 1 above, which is used for the hinge part of all polyimide.

  20. Copper foil having a thickness of 18 μm or less on a thermocompression-bonding multilayer polyimide film having a thickness of 5 to 25 μm, which has a thermoplastic polyimide layer on at least one side of the heat-resistant polyimide layer, and polyimide particles are dispersed in the thermoplastic polyimide layer A copper-clad laminated board made by laminating layers.

21. A continuous production method for a copper-clad laminate in which a copper film having a thickness of 1 to 18 μm is laminated by thermocompression bonding to a polyimide film having a thickness of 5 to 20 μm having a thermoplastic polyimide layer on one or both sides of the heat-resistant polyimide layer. ,
The thermoplastic polyimide layer of the polyimide film and the copper foil are continuously supplied to the laminating apparatus so as to overlap each other, and are laminated by thermocompression bonding at a temperature not lower than the glass transition temperature of the thermoplastic polyimide and not higher than 400 ° C. under pressure. Continuous manufacturing method for copper-clad laminate.

  Here, MIT folding resistance is based on JIS C6471, a copper foil circuit defined in the test method is formed only on one side, a radius of curvature of 0.8 mm, a load of 4.9 N, a bending speed of 175 times / This is a measurement of the number of folding resistances at the time when the initial electrical resistance value increased by 20% or more at a left and right folding angle of 135 degrees.

  Moreover, the tensile strength of copper foil is based on JIS * C6515, the test piece prescribed | regulated to the test method was produced, and the crosshead speed | rate measured by 2 mm / min.

  Further, the tensile strength ratio (%) after the heat treatment was calculated from the equation (1).

    Tensile strength ratio after heat treatment (%) = (Tensile strength after heat treatment) / (Tensile strength before heat treatment) × 100 (1)

  The copper-clad laminate of the present invention is obtained by laminating a copper foil having a thickness of 1 to 18 μm on one or both sides of a polyimide film having a thickness of 5 to 20 μm by thermocompression bonding. The thickness of the polyimide film is preferably 5 to 15 μm. The copper foil is preferably a rolled copper foil having a thickness of 12 μm or less, particularly 10 to 12 μm. In this way, by reducing the thickness of the polyimide film and the copper foil, the flexibility becomes very high. For example, when the thickness of the polyimide film was changed from 25 μm to 15 μm, the MIT folding resistance was about twice or more in both MD and TD. Further, even when the thickness of the copper foil was changed from 18 μm to 12 μm without changing the thickness of the polyimide film, the MIT folding resistance increased in both MD and TD.

In particular, the copper foil used is a rolled copper foil having a tensile strength before heat treatment of 300 N / mm ² or more and a tensile strength ratio after heat treatment at 180 ° C. for 1 hour defined by the above formula (1) of 33% or less. In this case, the flexibility is remarkably improved by reducing the thickness of the polyimide film and the copper foil.

  In the copper-clad laminate of the present invention, the MIT folding resistance is preferably about 2000 times or more in both MD and TD, and about 3000 times by selecting the thickness of the polyimide film and copper foil and the type of copper foil. More than about 3,700 times, further about 4000 times, further about 5000 times, further about 7000 times or more can be used.

  On the other hand, when the thickness of the copper foil and polyimide film is reduced, wrinkles occur at the roller contact portion in the process of the laminating method for obtaining a long copper-clad laminate, and the yield decreases due to poor appearance after lamination. There was a problem to do. In particular, with a polyimide film having a thickness of 25 μm or less, it was difficult to produce a continuous copper-clad laminate in terms of paper permeability.

  By using a thermocompression-bonding multilayer polyimide film having a thermoplastic polyimide layer in which polyimide particles are dispersed on one or both sides of a heat-resistant polyimide layer, the slidability of the polyimide film surface is improved and obtained. The resulting copper-clad laminate is free from defects such as wrinkles due to measurement over its entire length. In particular, a polyimide whose thermoplastic polyimide layer is at least 0.5 μm from the surface, preferably at least 0.7 μm from the surface, with a median diameter of 0.3 to 0.8 μm and a maximum diameter of 2 μm or less. The particles are dispersed in a proportion of about 0.5 to 10% by mass with respect to the polyimide of the polyimide surface layer, and preferably contain substantially no inorganic powder and have a thickness of 25 μm or less. Even if a thin polyimide film is used, a copper-clad laminate having no defective appearance can be obtained.

1 is a diagram showing SEM observation results (2000 times) of the surface of the polyimide film obtained in Example 1. FIG. FIG. 2 is a view showing SEM observation results (2000 times) of the surface of the polyimide film obtained in Reference Example 2. FIG.

1. Polyimide film used for the copper-clad laminate of the present invention The polyimide film used in the present invention has a thickness of 5 to 20 μm. The thickness of the polyimide film is preferably 5 to 18 μm, and more preferably 5 to 15 μm. By reducing the thickness of the polyimide film to 20 μm or less, preferably 18 μm or less, particularly 15 μm or less, the flexibility of the copper-clad laminate is greatly improved. This is not limited to a specific polyimide film, and the same effect can be obtained when applied to any polyimide film.

  Although it does not specifically limit as a polyimide film, It is obtained from the polyimide film used as a raw material of electronic components, such as a printed wiring board, a flexible printed circuit board, and a TAB tape, The acid component and diamine component which comprise this polyimide film, or this polyimide Examples thereof include a polyimide containing an acid component and a diamine component constituting the film.

The polyimide film used in the present invention preferably has at least one or more of the following characteristics.
1) A glass transition temperature of 300 ° C. or higher, preferably a glass transition temperature of 330 ° C. or higher, more preferably unidentifiable.
2) A linear expansion coefficient (50-200 degreeC) (MD) is a thing close | similar to the thermal expansion coefficient of metal foil, such as copper foil laminated | stacked on a polyimide film. Specifically, when copper foil is used as the metal foil, the thermal expansion coefficient of the polyimide film is preferably 5 × 10 ^{−6 to} 28 × 10 ⁻⁶ cm / cm / ° C., and 9 × 10 ^{−6 to} 20 more preferably × is ¹⁰ -6 cm / cm / ℃, is preferably further ^{12 × 10 -6 ~18 × 10 -6} cm / cm / ℃.
3) Tensile elastic modulus (MD, ASTM-D882) is 300 kg / mm ² or more, preferably 500 kg / mm ² or more, and more preferably 700 kg / mm ² or more.

  As a polyimide film, the thing which has a heat resistant polyimide layer and a thermoplastic polyimide layer, and the thermocompression-bonding multilayer polyimide film which has a thermoplastic polyimide layer on the one or both surfaces of a heat resistant polyimide layer are preferable. The thermoplastic polyimide layer is the surface on which the copper foil is thermocompression-bonded. Therefore, a double-sided copper-clad laminate is one that has a thermoplastic polyimide layer on both sides of a heat-resistant polyimide layer, and a single-sided copper-clad laminate is heat-resistant. A material having a thermoplastic polyimide layer on one side of the conductive polyimide layer is used.

  The glass transition temperature of the polyimide of the thermoplastic polyimide layer is lower than that of the heat-resistant polyimide, preferably 170 to 370 ° C, more preferably 170 to 320 ° C, and particularly preferably 190 to 300 ° C.

  The thickness of the heat-resistant polyimide layer is preferably about 3 to 18 μm, and the thickness of the thermoplastic polyimide layer is preferably about 1 to 6 μm.

  The polyimide of the heat-resistant polyimide layer has a glass transition temperature higher than that of the thermoplastic polyimide layer, preferably 300 ° C. or higher, more preferably 320 ° C. or higher, particularly preferably 350 ° C. or higher. It is preferable to use it.

  As described above, when the thickness of the polyimide film is reduced, excellent flexibility can be obtained. However, appearance defects such as wrinkles are likely to occur in the obtained copper-clad laminate. In order to improve the slipperiness of the polyimide film surface and to improve the appearance of the copper-clad laminate, it is preferable that polyimide particles are dispersed in the polyimide film surface or the thermoplastic polyimide layer. In particular, at least 0.5 μm from the surface of the polyimide film or the thermoplastic polyimide layer, preferably at least 0.7 μm from the surface, the median diameter is 0.3 to 0.8 μm and the maximum diameter is 2 μm or less. It is preferable that a certain polyimide particle is dispersed at a ratio of about 0.5 to 10% by mass with respect to the polyimide of the polyimide surface layer. Moreover, the polyimide film surface or the thermoplastic polyimide layer may contain inorganic powder or may not contain substantially.

  A thermocompression-bonding multilayer polyimide film containing polyimide particles in a thermoplastic polyimide layer can be produced, for example, as follows. First, a polyamic acid providing a thermoplastic polyimide having a glass transition temperature of 170 to 320 ° C., a polyamic acid solution composition containing polyimide particles as described above, and a polyimide core layer (heat resistant polyimide layer) comprising a heat resistant polyimide A polyamic acid solution containing a polyamic acid that gives a water is cast on a support so as to have a total thickness of 5 to 20 μm by a coextrusion-casting film forming method, and dried to form a self-supporting film. Form. And a polyimide film can be manufactured by peeling the obtained self-supporting film from a support body, heating, solvent removal, and imidation. The content of the polyamic acid in the polyamic acid solution composition for the thermoplastic polyimide layer is 16 to 22% by mass, and the content of the polyimide particles is 0.5 to 10% by mass with respect to the polyamic acid, preferably 0.5. It can be made into 5 mass%. Moreover, content of the polyamic acid in the polyamic acid solution for heat resistant polyimide layers can be 16-22 mass%.

  Or the thermocompression-bonding multilayer polyimide film which contains a polyimide particle in a thermoplastic polyimide layer can also be manufactured as follows. First, a polyamic acid solution that gives a polyimide core layer (heat-resistant polyimide layer) made of heat-resistant polyimide is cast on a support and dried to form a self-supporting film. The final thickness is preferably about 3 to 18 μm. Next, the polyamic acid which gives the thermoplastic polyimide whose glass transition temperature is 170-370 degreeC and the above polyimide particles are 0.5-10 mass% with respect to polyamic acid at least on one side of this self-supporting film. The polyamic acid solution composition for the surface layer, preferably contained at a ratio of 0.5 to 5% by mass, is applied and dried so that the thickness after drying is about 1 μm or more. If necessary, the surface layer polyamic acid solution composition is applied to the other surface so that the thickness after drying is about 1 μm or more. Then, a polyimide film can be manufactured by heating to remove the solvent and imidize.

  In addition, the thermocompression-bonding multilayer polyimide film which does not contain polyimide particles in the thermoplastic polyimide layer does not add polyimide particles to the polyamic acid solution composition for the surface layer in the above production method, and appropriately adjusts the concentration of polyamic acid. It can be manufactured by adjusting.

  As a polyimide of the thermoplastic polyimide layer, it has a thermocompression bonding property between a tape material of an electronic component such as a printed wiring board, a flexible printed circuit board, a TAB tape, and a COF board or a heat-resistant polyimide and a copper foil, or heat under pressure. A known polyimide that can have pressure-bonding properties can be used.

  As the polyimide of the thermoplastic polyimide layer, it is possible to use a polyimide having a thermocompression bonding property that can be bonded to the copper foil at a temperature not lower than the glass transition temperature of the thermocompression bonding polyimide and not higher than 400 ° C.

The polyimide of the thermoplastic polyimide layer is
(1) 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride, pyromellitic dianhydride, 3,3 ′ , 4,4′-benzophenonetetracarboxylic dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, bis (3,4-dicarboxyphenyl) sulfide dianhydride, bis (3,4- Dicarboxyphenyl) sulfone dianhydride, bis (3,4-dicarboxyphenyl) methane dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride and 1,4-hydroquinone dibenzoate An acid component containing at least one component selected from acid dianhydrides such as −3,3 ′, 4,4′-tetracarboxylic dianhydride, preferably at least 70 mol% of these acid components; Preferably 80 mol% or more, more preferably an acid component comprising 90 mol% or more,
(2) 1,3-bis (4-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 3,3′-diaminobenzophenone, 4,4′-bis (3-aminophenoxy) biphenyl, 4,4′-bis (4-aminophenoxy) biphenyl, bis [4- (3-aminophenoxy) phenyl] ketone, bis [4- (4-amino Phenoxy) phenyl] ketone, bis [4- (3-aminophenoxy) phenyl] sulfide, bis [4- (4-aminophenoxy) phenyl] sulfide, bis [4- (3-aminophenoxy) phenyl] sulfone, bis [ 4- (4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] ether, bis [4- (4 A component selected from diamines such as aminophenoxy) phenyl] ether, 2,2-bis [4- (3-aminophenoxy) phenyl] propane, and 2,2-bis [4- (4-aminophenoxy) phenyl] propane A diamine component containing at least one kind, preferably a polyimide obtained from a diamine component containing at least 70 mol% or more, more preferably 80 mol% or more, more preferably 90 mol% or more of these diamine components can be used.

As an example of a combination of an acid component and a diamine component that can obtain a polyimide of the thermoplastic polyimide layer,
(1) At least one component selected from 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride acid dianhydride An acid component containing seeds, preferably an acid component containing at least 70 mol% or more, more preferably 80 mol% or more, more preferably 90 mol% or more of these acid components;
(2) 1,3-bis (4-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, 4,4′-bis (3-aminophenoxy) biphenyl, bis [4- (3- Aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] ether, 2,2-bis [4- (3-aminophenoxy) phenyl] propane, 2,2-bis [4- (4- Aminophenoxy) phenyl] a diamine component containing at least one component selected from diamines such as propane, preferably at least 70 mol%, more preferably 80 mol%, more preferably 90 mol% or more. A polyimide obtained from a diamine component can be used.

As a diamine component that can obtain the polyimide of the thermoplastic polyimide layer, in addition to the diamine component shown above, in the range that does not impair the characteristics of the present invention,
m-phenylenediamine, 3,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfone, 3 4,4′-diaminodiphenylsulfone, 4,4′-diaminodiphenylsulfone, 3,3′-diaminobenzophenone, 4,4′-diaminobenzophenone, 3,4′-diaminobenzophenone, 3,3′-diaminodiphenylmethane, 4, , 4'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 2,2-di (3-aminophenyl) propane, 2,2-di (4-aminophenyl) propane, and other diamine components can be used.

  As a specific example of the polyimide of the thermoplastic polyimide layer, 1,3-bis (4-aminophenoxy) benzene and 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride and 3,3 ′, 4, Thermally fusible polyimide or 4,4-diamino obtained by copolymerizing both components with 4′-biphenyltetracarboxylic dianhydride at a ratio (molar ratio) of 20/80 to 80/20 Examples thereof include polyimide obtained by polymerizing diphenyl ether and 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride.

  Further, as specific examples of the polyimide of the thermoplastic polyimide layer, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride Aromatic tetracarboxylic dianhydrides such as bis (3,4-dicarboxyphenyl) methane dianhydride and bis (3,4-dicarboxyphenyl) ether dianhydride and 1,3-bis (4-amino) And a polyimide obtained by polymerizing and imidizing an aromatic diamine such as phenoxy) benzene or 1,3-bis (3-aminophenoxy) benzene.

The polyimide of the thermoplastic polyimide layer preferably has at least one or more of the following characteristics.
1) The thermocompression bonding polyimide (S2) has a peel strength of 0.7 N / mm or more between the metal foil and the polyimide (S2), and a peel strength retention of 90% or more even after heat treatment at 150 ° C. for 168 hours, Further, the polyimide should be 95% or more, particularly 100% or more.
2) The tensile modulus is 100 to 700 Kg / mm ² as a single polyimide film.
3) As a single polyimide film, the linear expansion coefficient (50 to 200 ° C.) (MD) is 13 to 30 × 10 ⁻⁶ cm / cm / ° C.

  As the heat-resistant polyimide layer, it is preferable to use a heat-resistant polyimide constituting a base film that can be used as a tape material for electronic components such as a printed wiring board, a flexible printed circuit board, a TAB tape, and a COF board.

As the heat-resistant polyimide of the heat-resistant polyimide layer,
(1) 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, pyromellitic dianhydride and 1,4-hydroquinone dibenzoate-3,3 ′, 4,4′-tetracarboxylic acid bis An acid component containing at least one component selected from anhydrides, preferably an acid component containing at least 70 mol% or more, more preferably 80 mol% or more, more preferably 90 mol% or more of these acid components;
(2) A diamine component containing at least one component selected from p-phenylenediamine, 4,4′-diaminodiphenyl ether, m-tolidine and 4,4′-diaminobenzanilide, preferably at least 70 mol of these diamine components. %, More preferably 80 mol% or more, and more preferably, polyimide obtained from a diamine component containing 90 mol% or more can be used.

As an example of a combination of an acid component and a diamine component constituting the heat-resistant polyimide,
1) 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, p-phenylenediamine or p-phenylenediamine and 4,4-diaminodiphenyl ether,
2) 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and pyromellitic dianhydride, p-phenylenediamine or p-phenylenediamine and 4,4-diaminodiphenyl ether,
3) pyromellitic dianhydride, p-phenylenediamine and 4,4-diaminodiphenyl ether,
4) What is obtained by using 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and p-phenylenediamine as main components (50 mol% or more in a total of 100 mol%) is a printed wiring board, It is used as a material for electronic components such as flexible printed circuit boards and TAB tapes. They have excellent mechanical properties over a wide temperature range, long-term heat resistance, excellent hydrolysis resistance, high thermal decomposition starting temperature, low heat shrinkage and linear expansion coefficient, flame resistance It is preferable because of its superiority.

As an acid component that can obtain the heat-resistant polyimide of the heat-resistant polyimide layer, in addition to the acid component shown above, as long as the characteristics of the present invention are not impaired,
2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride Bis (3,4-dicarboxyphenyl) sulfide dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride, bis (3,4-dicarboxyphenyl) methane dianhydride, 2,2- Bis (3,4-dicarboxyphenyl) propane dianhydride, 2,2-bis (3,4-dicarboxyphenyl) -1,1,1,3,3,3-hexafluoropropane dianhydride, 2 Acid dianhydride components such as 2-bis [(3,4-dicarboxyphenoxy) phenyl] propane dianhydride can be used.

As a diamine component capable of obtaining the heat-resistant polyimide of the heat-resistant polyimide layer, in addition to the diamine component shown above, the range does not impair the characteristics of the present invention.
m-phenylenediamine, 3,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfone, 3 4,4′-diaminodiphenylsulfone, 4,4′-diaminodiphenylsulfone, 3,3′-diaminobenzophenone, 4,4′-diaminobenzophenone, 3,4′-diaminobenzophenone, 3,3′-diaminodiphenylmethane, 4, , 4'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 2,2-di (3-aminophenyl) propane, 2,2-di (4-aminophenyl) propane, and other diamine components can be used.

  As the polyimide of the heat-resistant polyimide layer, for example, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (hereinafter sometimes simply referred to as s-BPDA) and paraphenylenediamine (hereinafter simply referred to as PPD). And optionally further 4,4′-diaminodiphenyl ether (hereinafter sometimes abbreviated simply as DADE). In this case, the PPD / DADE (molar ratio) is preferably 100/0 to 85/15.

  In addition, as a polyimide of another heat-resistant polyimide layer, pyromellitic dianhydride (hereinafter sometimes simply referred to as PMDA), or 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, It is produced from an aromatic tetracarboxylic dianhydride that is pyromellitic dianhydride and an aromatic diamine such as benzenediamine or biphenyldiamine. As the aromatic diamine, paraphenylenediamine, aromatic diamine having PPD / DADE of 90/10 to 10/90, or meta-tolidine is preferable. In this case, BPDA / PMDA is preferably 0/100 to 90/10.

  Moreover, it is manufactured from pyromellitic dianhydride, paraphenylenediamine, and 4,4'-diaminodiphenyl ether as the polyimide of another heat resistant polyimide layer. In this case, DADE / PPD is preferably 90/10 to 10/90.

As the polyimide of the heat-resistant polyimide layer, those having at least one of the following features, those having at least two of the following features [1) and 2), a combination of 1) and 3), 2) and 3)], in particular What has all the following characteristics can be used.
1) A single polyimide film having a glass transition temperature of 300 ° C. or higher, preferably a glass transition temperature of 330 ° C. or higher, more preferably unidentifiable.
2) As a single polyimide film, a linear expansion coefficient (50 to 200 ° C.) (MD) is preferably close to the thermal expansion coefficient of a metal foil such as a copper foil laminated on the polyimide film. Specifically, when copper foil is used as the metal foil, the thermal expansion coefficient of the polyimide film is preferably 5 × 10 ^{−6 to} 28 × 10 ⁻⁶ cm / cm / ° C., and 9 × 10 ^{−6 to} 20 more preferably × is ¹⁰ -6 cm / cm / ℃, is preferably further ^{12 × 10 -6 ~18 × 10 -6} cm / cm / ℃.
3) As a single polyimide film, a tensile elastic modulus (MD, ASTM-D882) is 300 kg / mm ² or more, preferably 500 kg / mm ² or more, and further 700 kg / mm ² or more.

  The polyamic acid solution that gives heat-resistant polyimide can be obtained by polymerizing an aromatic diamine and aromatic tetracarboxylic dianhydride that give heat-resistant polyimide in an organic polar solvent by a conventional method.

  Examples of the organic polar solvent include amide solvents such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, and N-methylcaprolactam, dimethyl sulfoxide, hexamethylphosphoformamide, dimethyl sulfone, Examples include tetramethylene sulfone, dimethyltetramethylene sulfone, pyridine, and ethylene glycol.

  In the above-described method, it is preferable that the polyamic acid solution is cast-coated on a smooth support surface such as a stainless steel mirror surface or a belt surface to be semi-cured at 100 to 200 ° C. or dried before that. When the cast film is processed at a high temperature exceeding 200 ° C., the adhesiveness tends to be lowered in the production of the thermoplastic polyimide film. This semi-cured state or an earlier state means that it is in a self-supporting state by heating and / or chemical imidization.

  The polyamic acid solution composition for forming the thermoplastic polyimide layer contains a polyamic acid solution and polyimide particles that give a thermoplastic polyimide having a glass transition temperature of 170 to 320 ° C, preferably 190 to 300 ° C. The ratio of the polyimide particles is preferably 0.5 to 10% by mass, particularly preferably 0.5 to 5% by mass with respect to the polyamic acid. As the polyimide particles, wholly aromatic polyimide particles containing at least 80% of a pyromellitic acid component and a p-phenylenediamine component, a median diameter of 0.3 to 0.8 μm, and a maximum diameter of 2 μm or less are preferable.

  In order to obtain fully aromatic polyimide particles, equimolar amounts of an aromatic diamine and an aromatic tetracarboxylic acid component each containing 80% or more of p-phenylenediamine and pyromellitic dianhydride are added to the organic polar solvent. Add the mixture, add a dispersant if necessary, raise the temperature to about 160 ° C. with stirring in an inert gas atmosphere such as nitrogen gas, heat at this temperature for about 2 to 5 hours, then cool, Obtained as a solution mixture containing wholly aromatic polyimide particles. Usually, an aromatic diamine and an aromatic tetracarboxylic acid component may be added to the polar solvent so that the polyimide in the mixture is 3 to 10% by mass. As the polyimide particles, it is preferable to use the solution mixture thus obtained as it is or after removing or adding a polar solvent if necessary.

  When an aromatic diamine and an aromatic tetracarboxylic acid component in which p-phenylenediamine and pyromellitic dianhydride are 80% or more are used, the median diameter is 0.3 to 0.8 μm and the maximum diameter is 2 μm or less. Totally aromatic polyimide particles can be easily obtained. In addition, when the polyimide particles have a particle size within the above range, it is easy to form fine protrusions on the surface of the thermoplastic polyimide layer, which is suitable for a copper-clad laminate that requires a fine pattern.

  Here, the median diameter refers to a diameter corresponding to a 50% cumulative value of the cumulative distribution curve.

  Accordingly, the polyimide particles may be spherical, but may be columnar, dumbbell-shaped, or oval-spherical in which the ratio of the minor axis to the major axis is 2 to 10, particularly about 3 to 6. In the case of a columnar shape, a dumbbell shape, or an elliptical sphere, those having a minor axis of 0.05 to 0.5 μm and a major axis of 0.7 to 1.5 μm are preferable.

  Moreover, when a fine pattern is not calculated | required as a copper clad laminated substrate, the fully aromatic polyimide particle whose median diameter is 0.3-10 micrometers can be used.

  By the said structure, it has a polyimide surface layer which consists of a thermoplastic polyimide whose glass transition temperature is 170-320 degreeC, especially 190-300 degreeC, and does not contain an inorganic powder substantially, and both a static friction coefficient and a dynamic friction coefficient are 0. A thermocompression-bonding multilayer polyimide film having an improved slidability in which large protrusions are not formed on the film surface is obtained.

  The thermocompression-bonding multilayer polyimide film used in the present invention has at least one surface having heat-fusibility and a thickness of 5 to 20 μm. By combining this polyimide film having a thickness of 5 to 20 μm and a copper foil having a thickness of 18 μm or less, the MIT folding resistance is preferably about 2000 times or more in both MD and TD, and a good bending A copper-clad laminate having the properties can be obtained.

  Further, when the thermocompression-bonding multilayer polyimide film contains polyimide particles in the thermoplastic polyimide layer, the slipperiness of the polyimide film surface is improved, and the film is wound up on a winding roll at a speed of 1 m / min or more in a long length. In addition, a copper-clad laminate having no appearance defects such as wrinkles can be obtained by measurement over the entire length. In order to obtain a copper-clad laminate having a good appearance, it is not limited to those having a thickness of 20 μm or less, and it is effective to use a thermocompression-bonding multilayer polyimide film containing polyimide particles in a thermoplastic polyimide layer.

2. Copper foil used in the copper-clad laminate of the present invention The copper foil used in the present invention has a thickness of 1 to 18 μm, particularly 3 to 18 μm. The thickness of the copper foil is preferably 12 μm or less.

  As the copper foil, a rolled copper foil, an electrolytic copper foil, or the like can be used, but a more excellent copper-clad laminate can be obtained when the rolled copper foil is used. Moreover, copper foil with a carrier can also be used.

  The preferable range of the thickness of the copper foil varies depending on the copper foil used. In the case of a rolled copper foil, the thickness is preferably 8 to 18 μm, more preferably 10 to 18 μm, and particularly preferably 10 to 12 μm. In the case of the electrolytic copper foil, the thickness is preferably 7 to 12 μm, and more preferably 9 to 12 μm.

  Moreover, as copper foil, Rz which shows surface roughness is 3 micrometers or less, Especially Rz is 2 micrometers or less, Especially 0.5-1.5 micrometers is preferable. When Rz is small, the copper foil surface may be surface-treated.

  As such copper foil, rolled copper foil (Microhard Corp., VSBK, 18 μm), rolled copper foil (Microhard Corp., VSRD, 12 μm), rolled copper foil (Hitachi Cable Corp., HPF-ST12-E, 12 μm) , Rolled copper foil (Nikko Materials, BHY-13H-T, 18 μm), rolled copper foil (Nikko Materials, BHY-22B-T, 12 μm), rolled copper foil (Fukuda Metal Foil Powder Co., Ltd., RCF-T4X, 12 μm), rolled copper foil (Hitachi Cable, HPF-ST10-E, 10 μm), rolled copper foil (Nikko Materials, BHY-13H-HA, 18 μm), rolled copper foil (Nikko Materials, BHY-22B-HA) , 12 μm), electrolytic copper foil (Nippon Electrolytic Co., Ltd., HLB, 12 μm), electrolytic copper foil (Nippon Electrolytic Co., Ltd., HLB, 9 μm), electrolytic copper foil (Nippon Electrolytic Co., Ltd., HLS, 9 μm) It can be.

In the case of a rolled copper foil, it is preferable that the tensile strength before heat treatment is 300 N / mm ² or more and the tensile strength ratio after heat treatment at 180 ° C. for 1 hour defined by the above formula (1) is 33% or less. When such a rolled copper foil is used, a highly flexible copper-clad laminate is obtained, and the effect of improving the flexibility by thinning the polyimide and the copper foil of the present invention appears more remarkably. Examples of such rolled copper foil include rolled copper foil (Nikko Materials, BHY-13H-HA), rolled copper foil (Nikko Materials, BHY-22B-HA), and the like.

On the other hand, in the case of electrolytic copper foil, the tensile strength before heat treatment is 300 N / mm ² or more, and the tensile strength ratio after heat treatment at 180 ° C. for 1 hour defined by the above formula (1) is 60% or less. Is preferred.

  As the copper foil with a carrier, a copper foil having a thickness of 1 to 5 μm and a metal or ceramic carrier bonded with a heat-resistant bonding agent is preferable. Examples of the carrier include a copper foil having a thickness of about 12 to 35 μm, particularly 12 to 18 μm. Specific examples of the ultrathin copper foil with carrier include electrolytic copper foil with carrier (Nippon Electrolytic Co., Ltd., YSNAP-3B, thin copper thickness 3 μm, carrier copper foil thickness 18 μm) and the like.

  In the case of a copper foil with a carrier, the carrier is peeled off from the obtained copper-clad laminate and adjusted to a predetermined copper foil thickness, for example, 5 to 8 μm by electrolytic plating.

3. Copper-clad laminate of the present invention and method for producing the same The copper-clad laminate of the present invention is obtained by laminating a 1 to 18 μm thick copper foil on one or both sides of a polyimide film having a thickness of 5 to 20 μm as described above by thermocompression bonding. It is what. By combining a polyimide film having a thickness of 5 to 20 μm and a copper foil having a thickness of 1 to 18 μm, the MIT folding resistance is preferably about 2000 times or more in both MD and TD, and good bending A copper-clad laminate having the properties can be obtained.

  The total thickness of the copper-clad laminate of the present invention is preferably 51 μm or less, particularly preferably 39 μm or less, for a double-sided copper-clad laminate. In a single-sided copper-clad laminate, it is preferably 33 μm or less, particularly preferably 27 μm or less.

  The copper-clad laminate of the present invention is obtained by, for example, using a continuous laminating apparatus such as a roll laminate or a double belt press, and thermocompressing a copper foil on one or both sides of a thermocompression-bonding multilayer polyimide film under pressure, or under pressure. Obtained by laminating by thermocompression-cooling.

  The thermocompression-bonding multilayer polyimide film alone or the thermocompression-bonding multilayer polyimide film and the copper foil are inline immediately before being introduced into the continuous laminating apparatus at about 150 to 250 ° C., particularly at a temperature higher than 150 ° C. and lower than 250 ° C. It is preferable to preheat for about 120 seconds. A preheater such as a hot air supply device or an infrared heater is used for preheating. In-line means a device arrangement in which a preheating device is installed between the raw material feeding device and the crimping part of the continuous laminating device, and the device can be crimped immediately after preheating. Moreover, it is also preferable to interpose a protective material between the thermocompression-bonding multilayer polyimide film and / or copper foil and the belt or roller during lamination. In this way, a copper foil is laminated on at least one surface of the heat-resistant polyimide layer via a thermocompression-bonding polyimide layer, and there is no defective product appearance, and high dimensional stability (dimensional stability is 0.1% or less) A copper-clad laminate is obtained.

  The double belt press is capable of performing high-temperature heating and cooling under pressure, and is preferably a hydraulic type using a heat medium.

  Preheating in-line may cause poor appearance due to foaming in the laminated body after absorbing water from the atmosphere and contained in the polyimide, or foaming may occur during immersion in the solder bath during electronic circuit formation. It is possible to prevent the product yield from deteriorating. Although a method of installing the entire laminating apparatus in a furnace is also conceivable, the laminating apparatus is practically limited to a compact one and is not practical due to limitations on the shape of the copper-clad laminated substrate. Even if pre-heat treatment is performed in the outline, moisture is absorbed again by the time of stacking, which may cause poor appearance and reduced solder heat resistance due to foaming.

  In the copper-clad laminate of the present invention, the temperature of the thermocompression bonding zone of roll laminate or double belt press is preferably 20 from the glass transition temperature of thermocompression bonding polyimide (in the above-mentioned multilayer polyimide film, polyimide of the thermoplastic polyimide layer). Higher than 400 ° C. and higher than 400 ° C., in particular 30 ° C. higher than glass transition temperature and lower than 400 ° C. under pressure, and in the case of a double belt press, it is subsequently cooled under pressure in a cooling zone, Preferably, it can be manufactured by laminating a copper foil on one or both sides of a polyimide film after cooling to a temperature 20 ° C. or more lower than the glass transition temperature of the thermocompression bonding polyimide, particularly 30 ° C. or more.

  When the product is a copper-clad laminate with a single-sided metal foil, a highly heat-resistant film that can be easily peeled off, such as a high-heat-resistant film or metal foil having an Rz of less than 2 μm, preferably a polyimide film (manufactured by Ube Industries, Ltd., High heat-resistant resin films such as Upilex S) and fluororesin films, and metal foils such as rolled copper foils with small surface roughness and good surface smoothness can be used as protective materials. Laminate a protective material on the surface of the polyimide film that is not laminated with copper foil, and after lamination, this protective material may be removed from the laminate and wound up, or wound with the protective material laminated and removed during use. Also good.

  In particular, it is possible to achieve a take-up speed of 1 m / min or more by laminating by thermocompression-cooling under pressure using a double belt press, and it is long and has a width of about 400 mm or more, particularly about 500 mm. A copper-clad laminate with a wide appearance and high adhesive strength (90-degree peel strength: 0.7 N / mm or more, particularly 1 N / mm or more) and a good appearance so that no flaws are substantially observed on the surface of the metal foil. Can be obtained. Moreover, when a double belt press is used, the obtained copper-clad laminate preferably has an average dimensional change rate of L, C, and R (left end, center, right end in the film unwinding direction) in each width direction. Thus, both MD and TD become 0.1% or less at room temperature (only after drying after etching) and 150 ° C. (after-etching heat treatment), and the uniformity of dimensional change becomes high.

  In one embodiment of the present invention, the polyimide film and the copper foil are respectively supplied to a roll laminate or a double belt press in a roll state, and the copper-clad laminate is obtained in a roll state.

  The copper-clad laminate obtained by the present invention can be used as an electronic component substrate after being subjected to various processes such as roll winding, etching, and, in some cases, curling back, and then cut into a predetermined size. For example, it can be suitably used as a substrate for FPC, multilayer FPC, or flex-rigid substrate. In particular, a single-sided copper-clad laminate (overall thickness is 8 to 38 μm) or a double-sided copper-clad laminate (overall thickness is 11 to 56 μm) with a copper foil thickness of 3 to 18 μm and a polyimide film layer thickness of 5 to 20 μm. A multi-layer substrate satisfying high heat resistance, low water absorption, low dielectric constant, and high electrical characteristics can be obtained by bonding with a plurality of, for example, 2 to 10 layers and a heat-resistant polyimide adhesive (thickness 5 to 12 μm). .

  The copper-clad laminate of the present invention includes not only a long substrate but also a long substrate cut into a predetermined size (small width or short length).

The copper-clad laminate of the present invention can be produced by a known method other than the laminating method described above. For example,
(1) A method of casting or applying a polyamic acid solution, which is a polyimide precursor, to copper foil, drying and / or imidizing as necessary, and further heating as necessary.
(2) Cast or apply a thermoplastic polyimide precursor solution to a copper foil, dry and / or imidize if necessary, and then cast or apply a heat-resistant polyimide precursor solution to the thermoplastic polyimide layer. And then imidizing and further heating if necessary,
(3) A thermoplastic polyimide precursor solution is cast or applied to a copper foil, dried and / or imidized as necessary, and a thermoplastic polyimide layer is further cast or coated with a heat resistant polyimide precursor solution. Then, if necessary, dry and / or imidize, cast or apply a thermoplastic polyimide precursor solution to the heat-resistant polyimide layer, dry and / or imidize if necessary, and further heat as necessary It can be manufactured by the method. What laminated | stacked copper foil on the single area layer polyimide film obtained from said (1)-(3) further, two single area layer polyimide films obtained from said (1)-(3), (1) and (2 ), (1) and (1), (2) and (2), etc. can be used.

  In this specification, the evaluation method of the friction coefficient representing the slipperiness of the polyimide film is as follows.

  In accordance with the method described in ASTM D1894, a polyimide film that has been held and conditioned at 23 ° C., 60% RH for 24 hours is used as a substrate, and is adhered to a thread metal (6 cm × 6 cm) so that the same surface is rubbed together. The coefficient of friction was measured using a slip tester (load: 200 g, sliding speed: 150 mm / min). The value when the chart starts to move is displayed as a static friction coefficient, and the value when the chart is stabilized as a dynamic friction coefficient.

  In this specification, the evaluation method of the MIT folding resistance of the polyimide film and the copper-clad laminate is as follows unless otherwise specified.

  MIT folding resistance (copper-clad laminate) is based on JIS C6471, unless otherwise specified, forms a copper foil circuit defined in the same test method only on one side, has a radius of curvature of 0.8 mm, and a load of 4. The number of times of folding was measured at 9N, at a bending speed of 175 times / minute, and at a left / right bending angle of 135 degrees, when the initial electrical resistance value increased by 20% or more. For sampling, test pieces of 10 points were prepared from the entire width, and the average value of these was used as the MIT folding resistance value.

  The workability is determined by visually observing the occurrence of wrinkles between the feeding lines from the feeding machine to the press when the polyimide film is fed at a speed of 2 m / min. The case where there was occurrence of was marked as x.

  The external appearance of the copper-clad multilayer substrate is checked by a CCD camera for the occurrence of wrinkles on the entire length of the long copper-clad laminate substrate wound on a winding roll (outer diameter of the mandrel: 15 cm) at a speed of 2 m / min. The case where there was no appearance defect due to wrinkles was rated as “◯”, and the case where some appearance defects due to wrinkles occurred was marked as “X”.

  The size of the particulate polyimide is analyzed as follows.

  Using N, N-dimethylacetamide as a dispersion solvent, dispersed for 60 minutes with ultrasonic waves, measured in a measurement range of 0.02 to 1000 μm, and measured on a volume basis as a particle diameter reference by a laser diffraction-scattering particle size distribution measurement method. did. The slurry solution obtained by producing the particulate polyimide was dispersed for 60 minutes by an ultrasonic cleaner. The dispersion medium was put into the measurement cell, and the slurry solution dispersed therein was dropped and diluted so that the transmittance of the laser beam / lamp was 95 to 75%. Then, it measured by manual batch type cell measurement. Equipment: Laser diffraction-scattering particle size distribution measuring device (type: LA-910, manufactured by Horiba, Ltd.), measurement mode: manual batch cell measurement.

  In the shape analysis of the particulate polyimide, the shape of the particulate polyimide on the glass plate was confirmed by SEM observation.

The physical properties of other polyimide films were evaluated according to the following methods.
1) Glass transition temperature (Tg) of polyimide film: determined from a peak value of tan δ by a dynamic viscoelasticity method (tensile method, frequency 6.28 rad / sec, temperature rising rate 10 ° C./min).
2) Linear expansion coefficient of polyimide film (50 to 200 ° C.): An average linear expansion coefficient of 20 to 200 ° C. was measured by a TMA method (tensile method, heating rate 5 ° C./min).
3) Volume resistance of polyimide film: measured in accordance with ASTM D257.
4) Mechanical properties and tensile strength of polyimide film: Measured according to ASTM D882 (crosshead speed 50 mm / min).
Elongation rate: Measured according to ASTM D882 (crosshead speed 50 mm / min).
-Tensile elastic modulus: Measured according to ASTM D882 (crosshead speed 5 mm / min).
5) For MIT folding resistance (polyimide film), a test piece having a width of 15 mm was cut out over the entire width according to JIS C6471, the radius of curvature was 0.38 mm, the load was 9.8 N, the bending speed was 175 times / minute, and the left and right bending angles. The number of times until the polyimide film breaks at 135 degrees is measured.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated concretely, this invention is not restrict | limited to the following Example.

(Reference Example 1)
Production Example of Particulate Polyimide Particulate polyimide is prepared by dissolving p-phenylenediamine and pyromellitic dianhydride in N, N′-dimethylacetamide and adding a dispersant (despersant: 0.5% by mass of monomer). The resulting mixture was gradually heated to 160 ° C. with stirring (40 rpm) in a nitrogen atmosphere, and the resulting mixture was stirred for 3 hours after reaching this temperature. As a result of measuring the particle size distribution of the obtained particulate polyimide with a laser diffraction-scattering type particle size distribution measuring device, the median diameter was 0.3 μm and the distribution range was 0.1 to 1 μm. Moreover, as a result of confirming the shape of the particulate polyimide in SEM observation, the ratio of the minor axis to the major axis was a columnar particle having 3 to 6.

(Reference Example 2)
Example of production of slippery thermocompression-bonding multilayer polyimide film Paraphenylenediamine (PPD) and 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (s-BPDA) in N-methyl-2-pyrrolidone ) In a molar ratio of 1000: 998 so that the monomer concentration is 18% (weight%, the same applies hereinafter), and the reaction is carried out at 50 ° C. for 3 hours to give a polyamic acid solution having a solution viscosity of about 1500 poise at 25 ° C. (Doped for heat-resistant polyimide) was obtained. In addition, 1,3-bis (4-aminophenoxy) benzene (TPE-R) and 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride (a-BPDA) in N-methyl-2-pyrrolidone ) At a molar ratio of 1000: 1000 so that the monomer concentration is 22%, and triphenyl phosphate was added at 0.1% based on the monomer weight, and the mixture was reacted at 5 ° C. for 1 hour. To the obtained polyamic acid solution having a solution viscosity of about 2000 poise at 25 ° C., the particulate polyimide obtained in Reference Example 1 was added so as to be 4.0% by mass with respect to the monomer concentration (dope ( A dope for thermoplastic polyimide of the surface layer) was obtained. The obtained heat-resistant polyimide dope and thermoplastic polyimide dope are made of metal by using a film forming apparatus provided with a three-layer extrusion die (multi-manifold die) and changing the thickness of the three-layer extrusion die. It was cast on a support and continuously dried with hot air at 140 ° C. to form a solidified film. After peeling the solidified film from the support, the temperature is gradually raised from 200 ° C. to 320 ° C. in a heating furnace to remove the solvent and imidize the long three-layer extruded polyimide film on the take-up roll. Winded up. The obtained three-layer extruded polyimide film exhibited the following physical properties.

Thermocompression bonding polyimide film,
Thickness configuration: 3 μm / 9 μm / 3 μm (total 15 μm),
Static friction coefficient: 0.37,
Tg of thermoplastic aromatic polyimide: 260 ° C. (dynamic viscoelasticity method, tan δ peak value, the same applies hereinafter),
Tg of heat-resistant polyimide for core layer: 340 ° C. or higher,
Linear expansion coefficient (50 to 200 ° C.): 18 ppm / ° C. (TMA method)
Tensile strength, elongation: 460 MPa, 90% (ASTM D882),
Tensile modulus: 7080 MPa (ASTM D882),
MIT folding resistance: not broken up to 100,000 times
Volume resistance: 4 × 10 ¹⁶ Ω · cm (ASTM D257).

  Moreover, the SEM observation result (2000 times) of the surface of the obtained polyimide film is shown in FIG.

(Reference Example 3)
Example of production of thermocompression-bonding multilayer polyimide film Except that polyimide particles were not added to the dope for thermoplastic polyimide on the polyimide surface layer, a long three-layer extruded polyimide film was used as a winding roll in the same manner as in Reference Example 2. Winded up. The obtained three-layer extruded polyimide film exhibited the following physical properties.

Thermocompression bonding polyimide film,
Thickness configuration: 3 μm / 9 μm / 3 μm (total 15 μm),
Static friction coefficient: 1.00 or more.

Example 1
Obtained in Reference Example 2 which was heated with hot air of 200 ° C. for 30 seconds in advance immediately before double belt pressing in one set of two rolled rolled copper foils (Tough pitch copper, Microhardware, VSBK, thickness 18 μm) The heat-bondable multilayer polyimide film (thickness: 15 μm) was heated at a heating zone temperature (maximum heating temperature): 330 ° C., a cooling zone temperature (minimum cooling temperature): 180 ° C., and a pressure bonding pressure: 40 kg / cm ² (3 0.9 MPa), with a crimping time of 2 minutes, and continuously laminated by thermocompression-cooling and winding a copper-clad laminate (width: 540 mm, length: 1000 m) of a roll-shaped double-sided copper foil on a take-up roll I took it. The evaluation results for the obtained copper-clad laminate are as follows.

MIT folding endurance: MD / TD = 2210 times / 2500 times,
Workability: ○,
Product appearance: ○.

  Moreover, the SEM observation result (2000 times) of the surface of the obtained polyimide film is shown in FIG.

(Example 2)
Winding a copper-clad laminate of rolled-up double-sided copper foil in the same manner as in Example 1 except that it was changed to one set of two rolled copper foils (Tough pitch copper, Microhardware, VSRD, thickness 12 μm). It was wound up on a take-up roll. The evaluation results for the obtained copper-clad laminate are as follows.

MIT folding endurance: MD / TD = 3100 times / 3320 times,
Workability: ○,
Product appearance: ○.

(Example 3)
A copper-clad roll-rolled double-sided copper foil in the same manner as in Example 1 except that it was changed to one roll of rolled copper foil (tough pitch copper, Hitachi Cable, HPF-ST10-E, thickness 10 μm). The laminated substrate was wound up on a winding roll. The evaluation results for the obtained copper-clad laminate are as follows.

MIT folding resistance: MD / TD = 3210 times / 3250 times,
Workability: ○,
Product appearance: ○.

Example 4
A roll-wrapped double-sided copper foil copper-clad laminate is used as a take-up roll in the same manner as in Example 1 except that two rolls of electrolytic copper foil (Nippon Electrolytic Co., Ltd., HLB, thickness 9 μm) are used. Winded up. The evaluation results for the obtained copper-clad laminate are as follows.

MIT folding resistance: MD / TD = 3210 times / 3250 times,
Workability: ○,
Product appearance: ○.

(Example 5)
In the same manner as in Example 1, except that it was changed to one set of two roll-wound electrolytic copper foils with carrier copper foil (Nippon Electrolytic Co., Ltd., YSNAP-3B, carrier copper foil thickness 18 μm, thin copper foil thickness 3 μm). A copper-clad laminated substrate with a wound double-sided copper foil was wound around a winding roll. The evaluation results for the obtained copper-clad laminate are as follows. The MIT folding resistance was measured on a test piece obtained by peeling the carrier copper foil and setting the thickness of the thin copper foil to 8 μm by electrolytic copper plating.

MIT folding resistance: MD / TD = 2120 times / 2160 times,
Workability: ○,
Product appearance: ○.

(Example 6)
The thermoplastic polyimide layer obtained in Reference Example 3 uses a thermocompression-bonding multilayer polyimide film (thickness: 15 μm) that does not contain polyimide particles, and is the same as in Example 1 except that the feed rate is halved. A copper-clad laminate of wound double-sided copper foil was wound up on a winding roll. The obtained copper-clad laminate had the same MIT folding resistance as that of Example 1, but the evaluation results of workability and product appearance were as follows.

Workability: x,
Product appearance: x.

(Example 7)
A hinge member with a pitch of 90 μm was prepared from the copper-clad laminate obtained in Example 4, and a coverlay (polyimide layer thickness: 25 μm, adhesive layer thickness: 25 μm) was bonded to perform an MIT folding resistance test. . As a result, MD / TD = 5000 times / 4000 times, and it was confirmed that the hinge member exhibited good characteristics. Moreover, since the holding property is excellent, a favorable hinge member was obtained when mounting by folding on the seam.

  The MIT folding resistance was measured according to JIS C6471, with a radius of curvature of 0.38 mm, a load of 4.9 N, a bending speed of 175 times / minute, and a right and left bending angle of 135 degrees.

(Reference Example 4)
The polyimide films used in Examples 8 to 14 and Comparative Examples 1 to 6 were produced as follows.

  In N-methyl-2-pyrrolidone, paraphenylenediamine (PPD) and 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (s-BPDA) were mixed at a monomer ratio of 1000: 998. It added so that it might become 18% (weight%, and the following is the same), and it was made to react at 50 degreeC for 3 hours, and obtained the polyamic acid solution (dope for heat resistant polyimide) whose solution viscosity in 25 degreeC is about 1500 poise. In addition, 1,3-bis (4-aminophenoxy) benzene (TPE-R) and 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride (a-BPDA) in N-methyl-2-pyrrolidone ) And 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (s-BPDA) in a molar ratio of 1000: 200: 800, so that the monomer concentration is 18% and also triphenyl. Phosphate was added in an amount of 0.5% by weight based on the monomer weight, and reacted at 40 ° C for 3 hours. The solution viscosity at 25 ° C. of the obtained polyamic acid solution was about 1680 poise. The particulate polyimide obtained in Reference Example 1 was added so as to be 4.0% by mass with respect to the monomer concentration to obtain a dope (surface layer thermoplastic polyimide dope). The obtained heat-resistant polyimide dope and thermoplastic polyimide dope are made of metal by using a film forming apparatus provided with a three-layer extrusion die (multi-manifold die) and changing the thickness of the three-layer extrusion die. It was cast on a support and continuously dried with hot air at 140 ° C. to form a solidified film. After peeling the solidified film from the support, the temperature is gradually raised from 200 ° C. to 320 ° C. in a heating furnace to remove the solvent and imidize the long three-layer extruded polyimide film on the take-up roll. Winded up. The obtained three-layer extruded polyimide film exhibited the following physical properties.

Thermocompression-bonding multilayer polyimide film (15 μm),
Thickness configuration: 3 μm / 9 μm / 3 μm (total 15 μm),
Static friction coefficient: 0.37,
Tg of thermoplastic aromatic polyimide: 240 ° C. (dynamic viscoelasticity method, tan δ peak value, hereinafter the same),
Tg of heat-resistant polyimide for core layer: 340 ° C. or higher,
Linear expansion coefficient (50 to 200 ° C.): 19 ppm / ° C. (TMA method)
Tensile strength, elongation: 460 MPa, 90% (ASTM D882),
Tensile modulus: 7080 MPa (ASTM D882),
MIT folding resistance: not broken up to 100,000 times
Volume resistance: 4 × 10 ¹⁶ Ω · cm (ASTM D257).

Thermocompression-bonding multilayer polyimide film (20 μm),
Thickness configuration: 3.5 μm / 13 μm / 3.5 μm (total 20 μm),
Static friction coefficient: 0.36,
Tg of thermoplastic aromatic polyimide: 240 ° C.
Tg of heat-resistant polyimide for core layer: 340 ° C. or higher,
Linear expansion coefficient (50 to 200 ° C.): 18 ppm / ° C. (TMA method)
Tensile strength, elongation: 510 MPa, 100% (ASTM D882),
Tensile modulus: 7140 MPa (ASTM D882),
MIT folding resistance: not broken up to 100,000 times
Volume resistance: 3 × 10 ¹⁶ Ω · cm (ASTM D257).

Thermocompression-bonding multilayer polyimide film (25 μm),
Thickness configuration: 4 μm / 17 μm / 4 μm (total 25 μm),
Static friction coefficient: 0.39,
Tg of thermoplastic aromatic polyimide: 240 ° C.
Tg of heat-resistant polyimide for core layer: 340 ° C. or higher,
Linear expansion coefficient (50 to 200 ° C.): 18 ppm / ° C. (TMA method)
Tensile strength, elongation: 520 MPa, 105% (ASTM D882),
Tensile modulus: 7200 MPa (ASTM D882),
MIT folding resistance: not broken up to 100,000 times
Volume resistance: 4 × 10 ¹⁶ Ω · cm (ASTM D257).

(Example 8)
The polyimide film having a thickness of 15 μm obtained in Reference Example 4 and a rolled copper foil (Nikko Materials, BHY-13H-T, thickness 18 μm) are laminated by thermocompression bonding as follows, and a copper-clad laminate substrate is obtained. Produced.

  Heating zone temperature (maximum heating temperature): 330 ° C, cooling zone temperature (minimum cooling) with polyimide film preheated by heating with 200 ° C hot air for 30 seconds in-line immediately before double belt press Temperature): 180 ° C., pressure bonding pressure: 3.9 MPa, pressure bonding time of 2 minutes, continuous thermocompression-cooling and laminating, roll-rolled copper foil copper-clad laminate (width: 540 mm, length) : 1000 m) was wound on a winding roll.

  And the MIT folding resistance of the obtained copper clad laminated substrate was measured.

  MIT folding resistance conforms to JIS C6471, a copper foil circuit specified in the same test method is formed only on one side, a radius of curvature of 0.8 mm, a load of 4.9 N, a bending speed of 175 times / minute, and a left and right bending angle. This is a measurement of the folding endurance at a time when the initial electrical resistance value increased by 100% at 135 degrees. For sampling, test pieces of 10 points were prepared from the entire width, and the average value of these was used as the MIT folding resistance value.

Rolled copper foil used had a tensile strength before the heat treatment is 433N / mm ² at 450 N / ^mm 2, TD in MD, 180 ° C., which is defined by the formula (1), the tensile strength ratio after 1 hour heat treatment The MD was 43% and the TD was 40%.

The tensile strength of the copper foil was measured at a crosshead speed of 2 mm / min by preparing a test piece defined in the same test method in accordance with JIS C6515. The average value of the five measured values was taken as the tensile strength. Further, the tensile strength ratio (%) after the heat treatment was calculated from the equation (1).
Tensile strength ratio after heat treatment (%) = tensile strength after heat treatment / tensile strength before heat treatment × 100 (1)

  These results are shown in Table 1.

(Comparative Example 1)
A copper-clad laminate was prepared in the same manner as in Example 8 except that the polyimide film used was changed to one having a thickness of 25 μm, and the MIT folding resistance was measured. The results are shown in Table 1.

Example 9
A copper clad laminate was prepared in the same manner as in Example 8 except that the copper foil used was changed to a rolled copper foil (Nikko Materials, BHY-13H-HA, thickness 18 μm), and MIT folding resistance was measured. The results are shown in Table 1.

Rolled copper foil used had a tensile strength before the heat treatment is 437N / mm ² at 421N / ^mm 2, TD in MD, 180 ° C., which is defined by the formula (1), the tensile strength ratio after 1 hour heat treatment The MD was 22% and the TD was 20%.

(Comparative Example 2)
A copper-clad laminate was prepared in the same manner as in Example 9 except that the polyimide film used was changed to one having a thickness of 25 μm, and the MIT folding resistance was measured. The results are shown in Table 1.

(Example 10)
A copper-clad laminate was prepared in the same manner as in Example 8 except that the copper foil used was changed to a rolled copper foil (Nikko Materials, BHY-22B-T, thickness 12 μm), and MIT folding resistance was measured. The results are shown in Table 1.

Rolled copper foil used had a tensile strength before the heat treatment is 420N / mm ² at 417N / ^mm 2, TD in MD, 180 ° C., which is defined by the formula (1), the tensile strength ratio after 1 hour heat treatment The MD was 44% and the TD was 37%.

(Comparative Example 3)
A copper-clad laminate was prepared in the same manner as in Example 10 except that the polyimide film used was changed to one having a thickness of 25 μm, and the MIT folding resistance was measured. The results are shown in Table 1.

(Example 11)
A copper-clad laminate was prepared in the same manner as in Example 8 except that the copper foil used was changed to a rolled copper foil (Nikko Materials, BHY-22B-HA, thickness 12 μm), and MIT folding resistance was measured. The results are shown in Table 1.

Rolled copper foil used had a tensile strength before the heat treatment is 443N / mm ² at 461N / ^mm 2, TD in MD, 180 ° C., which is defined by the formula (1), the tensile strength ratio after 1 hour heat treatment MD was 21% and TD was 19%.

(Comparative Example 4)
A copper-clad laminate was prepared in the same manner as in Example 11 except that the polyimide film used was changed to one having a thickness of 25 μm, and the MIT folding resistance was measured. The results are shown in Table 1.

As is clear from Table 1, the copper-clad laminate using a polyimide film having a thickness of 15 μm was extremely superior in MIT folding resistance compared to the copper-clad laminate using a polyimide film having a thickness of 25 μm. Moreover, the MIT folding resistance was superior in the copper-clad laminate using a thinner copper foil having a thickness of 12 μm.

Moreover, the Example using the rolled copper foil whose tensile strength before heat processing is 300 N / mm < ² > or more and whose tensile strength ratio after heat processing for 1 hour and 180 degreeC defined by said Formula (1) is 33% or less. The copper-clad laminates of Nos. 9 and 11 had excellent MIT folding resistance.

(Example 12)
A copper-clad laminate was prepared in the same manner as in Example 8 except that the copper foil used was changed to an electrolytic copper foil (Nippon Electrolytic Co., Ltd., HLB, thickness 12 μm), and MIT folding resistance was measured. The results are shown in Table 2.

Electrolytic copper foil used has a tensile strength before the heat treatment is 512N / mm ² at 504N / ^mm 2, TD in MD, 180 ° C., which is defined by the formula (1), the tensile strength ratio after 1 hour heat treatment The MD was 50% and the TD was 49%.

(Example 13)
A copper-clad laminate was prepared in the same manner as in Example 12 except that the polyimide film used was changed to one having a thickness of 20 μm, and the MIT folding resistance was measured. The results are shown in Table 2.

(Comparative Example 5)
A copper-clad laminate was prepared in the same manner as in Example 12 except that the polyimide film used was changed to one having a thickness of 25 μm, and the MIT folding resistance was measured. The results are shown in Table 2.

(Example 14)
A copper-clad laminate was prepared in the same manner as in Example 8 except that the copper foil used was changed to an electrolytic copper foil (Nippon Electrolytic Co., Ltd., HLB, thickness 9 μm), and MIT folding resistance was measured. The results are shown in Table 2.

(Comparative Example 6)
A copper-clad laminate was prepared in the same manner as in Example 14 except that the polyimide film used was changed to one having a thickness of 25 μm, and the MIT folding resistance was measured. The results are shown in Table 2.

  As is clear from Table 2, the copper-clad laminate using a thinner polyimide film was superior in MIT folding resistance. Moreover, the MIT folding resistance was superior in the copper-clad laminate using a thinner copper foil having a thickness of 9 μm.

Claims (21)

It is a copper-clad laminated board formed by laminating copper foil on one or both sides of a polyimide film by thermocompression bonding,
The thickness of the polyimide film is 5 to 20 μm,
A copper-clad laminate having a copper foil thickness of 1 to 18 μm. The polyimide film has a heat-resistant polyimide layer and a thermoplastic polyimide layer,
The copper-clad laminate board according to claim 1, wherein the copper-clad laminate board is a copper-clad laminate board obtained by laminating a copper foil by thermocompression bonding on one side or both sides of a heat-resistant polyimide layer via a thermoplastic polyimide layer.   The copper-clad laminate according to claim 1, wherein the polyimide film has a thickness of 5 to 15 μm.   The copper-clad laminate according to claim 1, wherein the copper foil is a rolled copper foil having a thickness of 8 to 18 μm.   The copper-clad laminate according to claim 4, wherein the copper foil is a rolled copper foil having a thickness of 10 to 18 μm.   The copper-clad laminate according to claim 5, wherein the copper foil is a rolled copper foil having a thickness of 10 to 12 μm. The copper foil is a rolled copper foil having a tensile strength before heat treatment of 300 N / mm ² or more and a tensile strength ratio after heat treatment at 180 ° C. for 1 hour defined by the following formula (1) of 33% or less. The copper-clad laminate as described in 1.
Tensile strength ratio after heat treatment (%) = tensile strength after heat treatment / tensile strength before heat treatment × 100 (1) The copper foil is a copper foil with a carrier,
The copper-clad laminate according to claim 1, wherein the thickness of the copper foil from which the carrier is peeled is 1 to 5 μm.   A copper-clad laminate obtained by peeling the carrier from the copper-clad laminate according to claim 8 and then adjusting the thickness of the copper foil to 5 to 8 μm by copper plating.   The copper-clad laminate according to claim 1, wherein the MIT folding resistance is about 2000 times or more.   The copper-clad laminate according to claim 9, wherein the MIT folding resistance is about 2000 times or more.   The copper-clad multilayer substrate according to claim 1, wherein the polyimide film is a thermocompression-bonding multilayer polyimide film having a thermoplastic polyimide layer on one side or both sides of the heat-resistant polyimide layer.   The copper-clad laminate according to claim 12, wherein polyimide particles are dispersed in the thermoplastic polyimide layer. The polyimide film having a median diameter of 0.3 to 0.8 μm and a maximum diameter of 2 μm or less in a thermoplastic polyimide layer of at least 0.5 μm from the surface thereof is about 0. It is dispersed at a rate of 5 to 10% by mass, does not substantially contain inorganic powder,
The copper-clad laminate according to claim 13, wherein the polyimide film has a friction coefficient of 0.05 to 0.7.   The copper-clad laminate according to claim 13, wherein the polyimide particles are obtained from a pyromellitic acid component and a p-phenylenediamine component.   The copper-clad laminate according to claim 12, wherein the polyimide film has a thermoplastic polyimide layer having a thickness of 1 to 6 µm on both sides of a heat-resistant polyimide layer having a thickness of 3 to 18 µm.   The copper-clad laminate according to claim 12, wherein the thermocompression-bonding multilayer polyimide film and copper foil are thermocompression bonded under pressure at a temperature not lower than the glass transition temperature of the thermoplastic polyimide and not higher than 400 ° C.   The thermocompression-bonding multilayer polyimide film is obtained by laminating and integrating a thermocompression-bonding polyimide layer on one side or both sides of a heat-resistant polyimide layer by a coextrusion-casting film forming method. Copper-clad laminated board.   The copper-clad multilayer substrate according to claim 1, which is for an all-polyimide hinge part.   Copper foil having a thickness of 18 μm or less on a thermocompression-bonding multilayer polyimide film having a thickness of 5 to 25 μm, which has a thermoplastic polyimide layer on at least one side of the heat-resistant polyimide layer, and polyimide particles are dispersed in the thermoplastic polyimide layer A copper-clad laminated board made by laminating layers. A continuous production method for a copper-clad laminate in which a copper film having a thickness of 1 to 18 μm is laminated by thermocompression bonding to a polyimide film having a thickness of 5 to 20 μm having a thermoplastic polyimide layer on one or both sides of the heat-resistant polyimide layer. ,
The thermoplastic polyimide layer of the polyimide film and the copper foil are continuously supplied to the laminating apparatus so as to overlap each other, and are laminated by thermocompression bonding at a temperature not lower than the glass transition temperature of the thermoplastic polyimide and not higher than 400 ° C. under pressure. Continuous manufacturing method for copper-clad laminate.